<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{margin:0;padding:0;}
        div{
            box-sizing: border-box;
        }
        .parent{
            width:1000px;
            margin-left: auto;
            margin-right: auto;
            background: deeppink;  
        }
        .parent>div{
            width: 240px;
            height:300px;
            background: pink;
               
        }
        

    </style>

</head>
<body>
    <div class="parent row">   
    <div class="child"></div>
    <div class="child"></div>
    <div class="child"></div>
    <div></div>
    </div>

</body>
</html>